The map above shows 'Land Ownership' in Ontario, according to the NRVIS database (Natural Resources and Values Information System). It doesn't directly show Crown Land; rather it shows land that is Privately Owned, or land that is part of an Indian Reserve. However, it can be assumed that land that is not privately owned or part of a reserve is Crown Land. A couple of things to keep in mind while using this map:

Sometimes, the MNR web server will go down. In that case, you may not see the yellow 'ownership' layer show up on top of the base map. If this is the case, I'm sorry; there's nothing I can do about it other than wait until the server is back online.

The data may not be 100% current/accurate - don't use it for legal purposes

The area covered by this information is generally central and northern Ontario. I've blocked out the Southern Ontario area with the large red polygon; please don't bother asking about this area--I don't know where to find Crown Land data there.